Horn actuating switch



Nov. 18, 1969 R. E. CALDWELL ET AL 3,479,477

HORN ACTUATING SWITCH Filed Dec. 5, 1966 2 Sheets-Sheet 1 jfl 4/ M 3 w; o 7

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Nov. 18, 1969 R. E. CALDWELL ETAL 3,479,477

HORN ACTUATING SWITCH Filed Dec. 5, 1966 2 Sheets-Sheet 2 I l ELEL 202612 2? 629$??? A o uzs 6. 64.55. \'\W,

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United States Patent 3,479,477 HORN ACTUATING SWITCH Robert E. Caldwell and Louis G. Cass, Detroit, Mich., as-

signors to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Filed Dec. 5, 1966, Ser. No. 599,303 Int. Cl. H01h 9/00, 3/00 US. Cl. 200-6155 4 Claims ABSTRACT OF THE DISCLOSURE A switch contact mechanism having two contact plates normally separated by resilient means and provided with spacing members for maintaining the contact plates in operable relationship. The spacing members and contact plates are a unitary assembly and the spacing members define and limit the gap between the contact plates with great dimensional accuracy. Being a unitary assembly, the mechanism can be incorporated into a steering wheel assembly without altering the predetermined spacing between the contact plates.

This invention relates to switches and more especially to the construction and arrangement of a switch for use on the steering column of an automobile or the like. In particular, it relates to a switch contact assembly for use in a horn blowing switch mechanism.

The horn electrical circuit of a vehicle generally includes a switch contact assembly located at the hub of a steering wheel which is actuated by means of a horn ring or one or more spokes which extend radially outwardly from the hub. In the interest of safety, it is desirable for the operator of the vehicle to be able to sound the vehicle horn without taking his hand from the steering 'wheel. In order to accomplish this, it is necessary that the contacts of the switch contact assembly close upon slight or limited movement of the horn ring. This in turn requires a switch contact assembly in which the contacts are positioned close and very accurately with respect to each other. Thus far, this latter requirement has'presented a serious problem in that it is essentially impossible to maintain the close dimensional control needed to insure proper spacing of the contacts. For example, one type of commonly used switch is held together by other components of the steering wheel assembly, namely, the steering wheel hub and a flange of the horn ring. In this type, the components of the switch contact are first assembled at the bench and then, when incorporated into the steering wheel assembly, compressed and sandwiched between other components of of the steering Wheel assembly. While stops are usually provided in the form of bushings, they merely add to the tolerance variations existing in the other components and result in a condition where the spacing between the contacts cannot be accurately controlled. Elforts to overcome this problem have resulted in switches which are assembled directly on the steering wheel assembly. This approach has not been too successful since it genera lly requires hand assembly which is relatively time consuming and diflicult due to the limited working area involved and, therefore, incompatible with high volume production. More importantly, this approach does not provide for consistent spacing of the contacts due to the dimensional variations which occur in the components in the components of the steering wheel assembly to which the contact assembly is secured.

Accordingly, it is an object of this invention to provide an improved switch contact assembly for use on the upper end of the steering column of an automobile or the like.

3,479,477 Patented Nov. 18, 1969 Another object is to provide a switch contact assembly in which the maximum spacing between the contact can be accurately fixed prior to installation of the assembly on a steering wheel.

A further object is to provide a unitary switch contact assembly which can be mounted on a steering wheel assembly without altering the spacing between the switch contacts.

A still further object is to provide a horn blowing switch mechanism adapted for use and assembly with a vehicle steering wheel wherein the switch contacts may be easily and quickly interengaged without necessitating the removal of the operators grip upon the steering wheel.

Another object is to provide a horn sounding switch mechanism for use on the steering column of an automobile which is simple in construction and of low manufacturing cost.

Accordingly, in the present invention, a unitary switch contact assembly is provided which is composed of two generally dish shaped contact plates. The contact plates are normally maintained in an axially spaced relationship by resilient means capable of being compressed so as to permit engagement of the contact plates. To provide and maintain a preselected spacing between the contact plates, positioning means are incorporated into the switch mechanism which establish and maintain the maximum spacing between the contact plates. The positioning means are carried by one of the members of the switch contact assembly and therefore the spacing between the contacts is not depended upon, nor efiected by, other components of the steering Wheel assembly. Accordingly, the switch contact assembly can be assembled with a preselected contact spacing and this spacing will not change when it is subsequently incorporated into the steering wheel assembly.

The above and other objects, features and advantages of this invention will be apparent from the following detailed description of a preferred embodiment of the invention and from the accompanying drawings wherein:

FIGURE 1 is a fragmentary cross sectional view of a portion of a steering wheel assembly taken generally on the line 11 of FIGURE 2 showing a horn switch contact assembly mounted on the upper end of a steering column:

FIGURE 2 is a sectional view taken generally on the line 2-2 of FIGURE 1 showing the mounting of the steering wheel on a steering shaft and the mounting of the switch contact assembly on the steering wheel; and

FIGURE 3 is a sectional View taken generally on the line 3-3 of FIGURE 1 showing the position of various elements of the switch contact assembly and the mounting of a horn ring on the steering wheel assemblage.

Referring now to FIGURE 1 of the drawings, a steering wheel assembly, only partly shown, is generally indicated by the numeral 10 and has a centrally located hub portion 12 which is interconnected with a rim (not shown) by a plurality of radially extending bars 14. A centrally apertured unitary switch contact assembly indicated generally by the numeral 16 is disposed in hub portion 12 and a horn blowing ring is shown at 18 having a plurality of spokes 20 each of which extend generally radially outward over a bar 14. A cap or emblem cover (not shown) engageable with flange 22 of horn ring 18 may be employed to enclose hub portion -12.

As seen with reference to FIGURES 2 and 3, a centrally apertured metal plate member 24 is disposed about a steering column shaft 26 so as to rest upon a metal hub 28. If desired plate member 24 can be affixed to hub 28 such as by spot welding. Steering wheel assembly 10 is secured on steering shaft 26 by means of plate 24,

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3 washer 30 and nut 32 which threadably engages steering shaft 26.

The switch contact assembly of this invention indicated generally by the numeral 16 comprises a pair of generally annular dished shaped contact plates 34 and 36 each having generally radially outwardly extending lip portions 38 and 40, respectively, a pair of insulating members 42 and 44, resilient means 46 and positioning means 48. Insulating members 42 and 44 are generally annular shaped and are disposed on opposite sides of upper contact plate 36 so that it is sandwiched between the insulation members.

It will be noted that one of the novel features of the switch contact assembly is that the components thereof are securely retained in operative position without the need of being secured to other members of the steering wheel assembly. This is most important as it allows the spacing between the contact plates to be fixed before they are placed in the steering wheel assembly. Equally as important is the fact that the preselected spacing is not changed when the switch contact assembly is installed, as described hereinafter, as part of the steering wheel assembly. In the preferred form of the switch contact assembly, positioning means such as the abutments or rivet like members 48 (FIGURE 3) are circumferentially spaced about and secured to lower contact plate 34. These abutment members lie substantially between and normal to contact plates 34 and 36 and pass through apertures 50, 54 and 52 which are provided in insulating members 42, 44 and contact plate 36, respectively. Each of the abutment members 48 is provided with a head portion 56 which overlies the upper surface of insulating member 44 and thereby functions as a stop to limit or define the maximum spacing between the contact plates 34, 36.

A plurality of resilient members or springs 46 are positioned between lower contact plate 34 and insulating member 42 so as to maintain contact plates 34 and 36 in a normal axially spaced relationship. Springs 46 are retained in position by projections 58 formed in lower contact plate 34 and protuberances 60 provided in insulating member 42 and, as seen in FIGURE 1, are circumferentially spaced about the contact assembly and angularly displaced with respect to the abutment 48. As seen with reference to FIGURE 2 each of the protuberances 60 project through and extend above insulating member 44 and have a bore 62 in which a portion of the spring member 46 is retained. Each of the spring members 46 is thereby retained in a state of compression and therefore holds insulating member 44 against head portion 56 of rivet 48. Likewise, the upper contact plate 36 is held firmly between the insulating members 42 and 44.

As seen with particular reference to FIGURE 3, a horn blowing switch mechanism for use with a steering wheel is provided by interconnecting the unitary switch contact assembly 16 and a horn blowing ring 18 having at least one actuating spoke 20. Thus, lower contact plate 34 is provided with a plurality of clearance apertures 64 of a diameter large enough to permit a fastener 66 to be inserted therethrough and into threaded engagement with horn ring 18. The resulting horn blowing switch assembly can then be incorporated in the steering wheel assembly by placing lower contact plate 34 upon plate 24 and securing it to the steering wheel as by threaded fastener 68 (FIGURE 2) which may be inserted through apertures 70 and 72 formed in insulating member 44 and upper contact 36, respectively.

It will be recognized that apertures 50, 52 and 54 through which rivets 48 pass are of greater diameter than the rivet thereby permitting lip portion 40 of contact plate 36 to engage lip 38 of contact plate 34 when a spoke member 20 is pressed by the vehicle operator. It will also be recognized that the spacing between the contact plate is controlled by the axial length of the positioning means 48 and this spacing can be closely controlled as it is not effected by the other components of the steering wheel assembly. Therefore, dimensional variations which occur in other steering wheel assembly components do not have to be considered in providing for a close tolerance horn switch. Accordingly, an assembly can now be massed produced in which the distance between the peripheral lips of the Contact plates is as little as 0.020 of an inch. It has been found that employing contact plates having lip portions substantially parallel to the base portion thereof as 38 and 40 permits the attainment of closer tolerances with respect to the spacing between the contact plates as any metal stretch encountered in stamping of the contact plates is directed in a peripheral direction.

The upper contact 36 is provided with an upstanding finger 74 to which a wire (not shown) is connected that is assembled down the steering column to the horn mechanism. The circuit is grounded by means of lower contact 34 which is interconnected with plate 24. Pressing of any of the spokes 20 will cause the springs 46 to be compressed and plates 34 and 36 to make contact thereby closing the circuit through the horn.

It will be understood that the insulating members can be of any suitable plastic or rubber material and that the steering wheel assembly is of conventional construction including a metal spider and rim reinforcement welded together and to the hub and covered with a suitable plastic material.

As illustrated in the drawings the lower insulating member 42 is carried entirely between the contact plates 34, 36 while the upper insulating member 44 is provided with a lip portion 76 which extends across lip portions 38 and '40 of the contact plates thereby providing a shield to protect the rest of the steering wheel assembly in the event of arcing.

From the foregoing description it is apparent that the objects of this invention have been obtained. A switch contact assembly has been provided which is simple in construction and reliable in its action. Moreover, it enables the switch contacts to be closely positioned relative to each other so as to require a minimum of movement of the horn actuating spokes to close the horn circuit. It will be understood that modifications and variations may be effective without departing from the scope of the novel concepts of the present invention as defined in the appended claims.

We claim:

1. A unitary switch contact assembly adapted for use in a horn blowing switch mechanism comprising a pair of substantially annular contact plates, said contact plates being arranged such that at least one of said plates has at least a portion which is in engagea'ble relationship with the other of said contact plates, resilient means normally maintaining said contact plates in an axially spaced relationship, a plurality of abutments each carried by one of said contact plates effective for limiting and establishing the maximum space between said contact plates prior to installation of the switch contact assembly on the steering wheel, said abutments having a substantial portion thereof between and generally normal to said contact plates and being circumferentially spaced from each other and disposed so as to be in tension when said contact plates are in said spaced relationship, and electrical insulating means comprising a first insulating member carried between a portion of said abutments and one of said contact plates and a second insulating member disposed between said contact plates.

2. A contact assembly according to claim 1 wherein said second insulating member is provided with a plurality of protuberances which extend through said one of said contact plates and project beyond said first insulating member, said protuberances having internally formed spaces for the partial reception therein of said resilient means.

3. A unitary switch contact assembly adapted for use in a horn blowing switch mechanism comprising a pair of substantially annular contact plates, said contact plates being arranged such that at least one of said plates has at least a portion which is in engageable relationship with the other of said contact plates, a plurality of circumferentially spaced abutments carried by one of said contact plates effective for limiting and establishing the maximum space between said contact plates prior to installation of the switch contact assembly on the steering wheel and being disposed so as to have a substantial portion thereof between and generally normal to said contact plates, electrical insulating means comprising first and second insulating members each of which being disposed on an opposite side of the other of said contact plates, and a plurality of circumferentially spaced springs normallyimaintaining said contact plates in an axially spaced relationship, said springs being angularly displaced with respect to said abutments and in engagement with one of said contact plates and one of said insulating members.

4. A unitary switch contact assembly adapted for use in a horn blowing switch mechanism comprising a pair of contact plates, said contact plates *being arranged such that at least one of said plates has at least a portion which is in engageable relationship with the other of said contact plates, a plurality of abutments carried by one of said contact plates effective for limiting and establishing the maximum space between said contact plates prior to installation of the switch contact assembly on the steering wheel and being disposed so as to have a substantial portion thereof between and generally normal to said contact plates, electrical insulating means disposed on opposite sides of the other of said contact plates, and resilient means normally maintaining said contact plates in an axially spaced relationship, said resilient means being in engagement with one of said contact plates and said insulating means.

References Cited UNITED STATES PATENTS 2,273,757 2/1942 Kotliarevsky ZOO-61.54 2,894,090 7/1959 Timolf et a1. 20061.54X 2,061,222 11/1936 Creson 2006l.55 2,631,204 3/1953 Kibiger 200--61.55 3,154,647 10/1964 Muller et al. 200 61.56

ROBERT K. SCHAEFER, Primary Examiner R. A. VANDERHYE, Assistant Examiner US. Cl. X.R. 

